Post-Diet Plan: Fix Metabolic Adaptation, Eat Normally, Stay Lean

Most diets fail. Even if fat loss is achieved, rebounds are commonplace, and permanent changes are elusive.

It’s a cruel trick of our physiology—fat loss itself sets us up for easy fat gain when we return to normal eating. However, with the right strategy, it’s possible to transition back to normal eating while staying lean.

Post-Diet Disaster

The post-diet period is notoriously problematic. It’s the stage at which so many diets come undone with a rebound.

We’re inundated with actual fat loss methods, but the transition back to a way of eating that can be maintained long term is normally given no thought.

It makes no sense—getting back to normal eating is as important as the short term fat loss phase, at least if you want permanent body composition improvements.

Metabolic Adaptation

When you’ve lost a significant amount of fat, metabolic adaptation means you’re primed to regain it. Metabolic adaptation is caused by a number of things, including:

Changes to levels of various hormones. These changes have multiple effects that negatively impact quality of life, but with respect to fat gain specifically, we see:

Increased hunger.

Decreased satisfaction from eating.

More efficient use of food energy.

Lowered energy expenditure through reductions in movement, both conscious (ie, less willingness to voluntarily move) and subconscious (fidgeting, for instance).

Less overall body mass, which in and of itself burns energy.

These things make fat storage much more likely, even on an intake that wouldn’t have caused it before the diet. And the leaner you became during your fat loss phase, the more severe all these effects are.

How Much Does Metabolism Drop?

Metabolism decreases are highly individual and dependent on many factors. One of the most interesting and extreme looks at this was the Minnesota Starvation Experiment in which World War II conscientious objectors were subjected to semi-starvation conditions.

“… the adaptive component of metabolic rate reduction was only 15%. Which is about the largest drop ever measured (most studies measure less).”

So under extreme conditions, we can roughly expect a 15% drop in metabolic rate. You’d assume less than this given a well-thought-out, moderate approach to fat loss. However, for our purposes here let’s assume a full 15% drop. For staying lean it’s better to underestimate energy expenditure. It’s easy enough to shoot low and simply add more food if we need it rather than doing the opposite and having to diet again.

Recovery of Full Metabolic Function

Complete recovery of metabolism requires:

Increased food intake for a certain amount of time. The exact increase and amount of time depend on the degree of metabolic adaptation, how low calories got, extent of fat loss, time spent dieting, time spent at pre-diet weight, genetic propensities, and other variables.

A minimum amount of body fat. Beneath a certain level of leanness—which varies between people—full metabolic health is impossible. (Incidentally, I believe this minimum level can be lowered, having seen this happen in others, and having done it myself.)

It’s actually very easy to recover metabolism, and something most people do. If you remove all your dietary restrictions and follow your physiological urges, it will happen naturally.

However, it will normally also result in massive fat gain, which defeats the purpose of the diet.

Time and Calories Are Our Tools

If you want to keep the results of the hard work you put into your diet, obviously you can’t give in to uncontrolled binging. Going back to how you used to eat will probably also undo your progress.

All is not lost, however.

We have two variables to tweak for the purpose of returning to normal eating and full metabolic health while at the same time staying lean: time and caloric increase.

By carefully managing them, we can accomplish our goals.

The Post-Diet Plan

1. Kill the Deficit

If you’ve cut body fat, by definition you’ve been in an energy deficit (of course the body tops up the inadequate energy coming in from food by turning to stored body fat, which is how we lose fat in the first place).

The first step to post-diet recovery is to immediately eliminate the deficit. We need to get straight back to current maintenance intake—ie, an amount of food that neither causes further loss of body weight, nor exceeds energy demands and leads to fat gain.

It’s important to emphasize that maintenance calories will be lower than the time before the diet because of reduced body mass. Further, metabolic adaptation also means they’ll also be slightly lower than they would be at full metabolic health.

Establishing maintenance calories involves some trial and error. We can take an estimation of maintenance calories for a person who hasn’t been dieting, subtract 15% from it to account for metabolic adaptation, and we’ll have a conservative amount that can be built upon if need be.

A starting point for maintenance calories may be obtained a few ways.

As written about here, Lyle McDonald simply uses a range of 14-16 Calories per pound of body weight for a normal person at full metabolic health—you’d use 14 for someone with a naturally slow metabolism, 16 for someone with a fast metabolism.

A formula into which we put some of our vital statistics, such as that found here on tdeecalculator.net.

We then subtract our 15% metabolic adaptation allowance.

Of course these numbers are estimates. But they’re not a bad starting point, and because we’ve been so conservative with our -15% allowance for metabolic adaptation, there shouldn’t be much risk of body fat gain.

Example

Let’s take a person who has dieted down to 200 lb. We’ll use Lyle’s method for approximating maintenance intake, and assume this is a person with a naturally slow metabolism (meaning we use the low value of 14 as a multiplier).

200 x 14 = 2800 Calories

A daily intake of 2800 Calories is what we’d expect them to maintain their weight on if they hadn’t been dieting. However, our person has, so to account for metabolic adaptation, we subtract 15% from that.

2. Monitor

Scale Weight

I strongly advise recording daily weight—at the same time under the same conditions every day to track progress.

Any needed adjustments should be based on a running seven day average of these measurements. This is because body weight can naturally fluctuate a lot from day to day, and isn’t necessarily indicative of changes in body fat.

After the first caloric increase fat storage is unlikely, but a bump in scale weight is possible due to carbohydrate storage, extra digestive tract volume, and the water weight that both of those will cause.

It’s possible that weight could actually decrease as the extra energy helps improve sleep, reduce cortisol levels, improve workouts, and thereby squeeze out a bit more fat loss. Enjoy it while it lasts.

Skin-Folds, Photos, and Tape

As it stands, measuring body fat is very difficult (apparently the only reliable technique involves autopsy, which seems a little extreme). Scales are very useful, but natural swings in body weight make them a fairly blunt instrument, and the more data we have during this touchy process, the better.

So in addition I recommend taking a weekly skin-fold caliper measurement at one or two places you tend to accumulate body fat (I personally take a weekly reading on my lower abs. Every few months or so I’ll do a more comprehensive set including mid-thigh, lower-back, glutes, pecs, triceps, etc).

Note: it’s important to aim for consistency in technique so as to be sure changes seen are due to differences in body fat, not just measurement error. Also, don’t worry about trying to calculate body fat—it won’t be accurate, and isn’t especially useful for tracking progress. All we need is the measurement itself.

You can buy calipers quite cheaply (here at amazon.co.uk if you’re in the UK, and here at amazon.com if you’re in the US. Personally, I use and like these particular ones), and while they won’t be anything close to medical grade, they’ll be adequate for our purposes.

Photos are another must. Again, consistency is important in order to gauge real changes, so time of day, lighting, and location should all be kept the same. Strip down and take a few selfies in a mirror with your cellphone every week or two (or get a patient partner to take them for you).

Tape measure limb and torso circumferences are also useful. However, I think they’re better for gauging larger swings in body fat, which is exactly what we’re trying to avoid during this whole process. Therefore I take them only every few months or less.

If after a week nothing too drastic occurs in body weight or skin-fold measurements, we can move onto the next phase. If you’re particularly averse to the remotest possibility of fat gain, wait two weeks.

3. Reverse Diet to Recover Full Metabolism

This is the magic bit, and what really makes permanent reductions to body fat possible. By addressing the reduced energy expenditure we incurred through fat loss, we can build up eating capacity to return to a normal, enjoyable lifestyle instead of having to permanently endure a more limited food intake.

Dieting normally involves incremental calorie reductions over time as and when needed to overcome plateaus. Reverse dieting is the opposite—the slow addition of food over time with the goal of nursing metabolism back to full capacity.

Jumping straight back up to predicted normal maintenance calories after a diet will likely cause fat gain. Reverse dieting allows us to get to the same normal eating, but avoids the fat gain by giving the body time to adjust to small changes.

The goal of this phase is to increase the amount we eat to a maximum short of fat gain. We want to go from the suppressed maintenance level caused by fat loss up to the higher level of full metabolic health.

How averse you are to any possibility of fat gain will dictate your course of action. While weekly increases of 100 to daily calories will most likely be fine, the ultra-paranoid might opt for 50.

The same estimates we previously turned to can also be used here to find our target upper level of maintenance calories. Again with the proviso that they’re starting points that may need to be adjusted up or down depending on results. That is:

This target calorie number is what we build towards in weekly increments of 100 (or 50 if you’d like to be more conservative) after our first deficit-eliminating bump.

Example (With Troubleshooting)

To return to our 200 lb example, this person has ended their diet—let’s say they got down to 1900 Calories at the end of the fat loss phase. They immediately increased their daily energy intake to 2380.

A week passed, and both caliper measurements and scale weight remained stable. Therefore it was time to begin the reverse diet phase.

Remember, their predicted maintenance calories were 2800, so the reverse diet would take four weeks provided no fat gain was seen. But let’s throw in a few complications to illustrate how you might deal with them should they occur.

End of Diet Phase

Week 0: 1900 Calories

Deficit Elimination Phase

Week 1: 2380 Calories (rounded up to 2400)

Seven-day weight trend and skin-folds are stable and indicate no fat gain, time to start reverse diet.

Reverse Diet Metabolic Recovery Phase

Week 2: 2500 Calories

Week 3: 2600 Calories

Week 4: 2600 Calories

At this point, weight has trended up a couple of pounds and belly skin-folds are up by a few mm. Therefore our person decides to back calories down to 2500.

Week 5: 2500 Calories

The reduction seemed to put things back on track, but to be sure, one more week is spent at the same level.

Week 6: 2500 Calories

Still looking good, so on with the reverse diet.

Week 7: 2600 Calories

Week 8: 2700 Calories

Week 9: 2800 Calories

Post-Diet – Permanent Maintenance

We’re now at predicted maintenance, but measurements are dropping again. Therefore, one more week with no change to be sure.

Week 10: 2800 Calories

Even though we’re at predicted maintenance, scale weight and skin-fold measurements make our person feel they might be able to get away with an extra 100.

Week 11: 2900 Calories

Further weeks go by and measurements remain stable. Our person decides to try another few 100 Calorie increases, but once again weight and skin-folds begin to creep up.

Ultimately they have to dial back to 2900. This is the key number that allows maintenance of their desired body composition, but it’s quite high.

They’re lean and feel great. Metabolic rate is fully recovered, they can eat normally, and the whole project was a success.

Summary: The Post-Diet Plan

Eliminate deficit. Once desired leanness has been achieved on the fat loss phase of a diet, increase calories straight up to predicted maintenance* minus 15% (to conservatively account for metabolic adaptation). Stay at this intake for a week or two.

Reverse diet. Gradually eliminate the 15% subtraction in increments of 100 per week until you get to predicted maintenance. That is, each week add 100 Calories to your daily intake. If you’re ultra-paranoid about fat gain, make the increases just 50. Monitor scale weight and selected skin-folds, adjust if necessary.

Live the lean life. Maintain at this level and enjoy. Congratulations, you’ve worked hard and have done what few ever manage.

* Body weight in pounds multiplied by 14-16, depending on speed of natural metabolism and activity levels. Alternatively, use an online calculator.

Notes

This approach is most suitable for people who’re willing to track their food intake. But if that’s you and you’re not afraid to put the effort in, the results can be incredible. Even if you were obese at your worst (like I was), it’s possible to get very lean and stay that way.

Exercise should be continued as usual throughout this whole process. I recommend resistance training in particular—it has extremely complementary effects on body composition, plus many health benefits besides.

If extra cardiovascular exercise was a part of your fat loss protocol, it should be gradually stepped back at the start of this post-diet plan to your normal level. (Personally I never do cardio, but that’s only because it’s not something I enjoy. I also don’t think it’s necessary for fat loss.)

See here for guidelines on exactly what to eat (in a nutshell—cover protein needs, then fill in the rest with whatever you please).

Conclusion: Permanent Leanness

Losing body fat is way too much effort to flush away your results like most do by not planning for the time after the diet.

Instead, by using the techniques here, you can retain the hard work you put into your fat loss, and stay lean for life.

Feedback is very welcome, It’d be great to hear your thoughts and about your experiences. Just use the comment form below, or send me an email.

If you enjoyed this, take a look at Reverse Dieting and Metabolic Whiplash, which is about the time I mistakenly thought I had turned into a metabolic superman. I went way above my predicted maintenance on a reverse diet, only to very suddenly get fat…

Thank you so much for reading.

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